I've never been much of a fan of high tire pressure. It seems like any gains due to reduced rolling resistance are more than lost when your rock hard tire loses traction on gravel or under hard acceleration. I usually run my tires on my single bike at around 100psi and have never felt like I was at a competitive disadvantage. On the tandem, I've been running the 28s at about 120psi in the rear and 110psi in the front. I'm wondering if with smaller tires it will really be necessary to go above 120psi to avoid pinch flats?